LM1815

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SNOSBU8F – SEPTEMBER 2000 – REVISED MARCH 2013

LM1815 Adaptive Variable Reluctance Sensor Amplifier

Check for Samples: LM1815

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FEATURES

DESCRIPTION

The LM1815 is an adaptive sense amplifier and

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Adaptive Hysteresis

default gating circuit for motor control applications.

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Single Supply Operation

The sense amplifier provides a one-shot pulse output

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Ground Referenced Input

whose leading edge coincides with the negative-

going zero crossing of a ground referenced input

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True Zero Crossing Timing Reference

signal such as from a variable reluctance magnetic

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Operates from 2V to 12V Supply Voltage

pick-up coil.

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In normal operation, this timing reference signal is

with External Resistor

processed (delayed) externally and returned to the

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CMOS Compatible Logic

LM1815. A Logic input is then able to select either

the timing reference or the processed signal for

APPLICATIONS

transmission to the output driver stage.

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Position Sensing with Notched Wheels

The adaptive sense amplifier operates with a positive-

going threshold which is derived by peak detecting

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Zero Crossing Switch

the incoming signal and dividing this down. Thus the

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Motor Speed Control

input hysteresis varies with input signal amplitude.

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Tachometer

This enables the circuit to sense in situations where

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Engine Testing

the high speed noise is greater than the low speed

Connection Diagram

Figure 1. Top View

14-Lead SOIC or PDIP

See D or NFF0014A Package

These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam

during storage or handling to prevent electrostatic damage to the MOS gates.

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Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

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PRODUCTION DATA information is current as of publication date.

Copyright © 2000–2013, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.